SB Emulation in MS-DOS/ Window 95/98 B-3
Interrupt Request (IRQ)
Line
An IRQ line is a signal line that a device uses
to notify your computer’s central processor
that it wants to send or receive data for
processing.
Direct Memory Access
(DMA) Channel
A DMA channel is a data channel that a device
uses to transfer data directly to and from the
system memory.
Understanding the
Environment
Variables
Environment variables are used to pass
hardware configuration information to the
software in your system. For MS-DOS, your
audio card includes the following:
❑
❑
CTSYN Environment
Variable
The
CTSYN
environment variable points to the
location of the CTSYN.INI file, which usually
resides in the Windows directory. The syntax
for this variable is as follows:
CTSYN=path
where path is the location of the CTSYN.INI
file.
BLASTER Environment
Variable
The BLASTER environment variable
specifies the base I/O address, IRQ line, and
DMA channels of the SB interface. Its syntax
is:
BLASTER=A220 I5 D1 H5 P330 T6
The parameters in the command are as
follows.
This
Parameter Specifies
Axxx
SB interface’s base I/O
address.
Ix
IRQ line used by the
audio interface.
Dx
First DMA channel used
by the audio interface.
Hx
Second DMA channel
used by the audio
interface.
Pxxx
MPU-401 UART
interface’s base I/O
address.
Tx
Card type. x must be 6.
Determining
Resources
To find the current SB PCI512 SB16
Emulation resources in Windows 95/98:
1. Click the Start button, point to Settings,
and then click Control Panel.
2. In the Control Panel window, double-click
the System icon.
3. In the System Properties dialog box, click
the Device Manager tab.
Table B-2: Possible default interrupt request
(IRQ) line assignment.
Device
Default IRQ Line
SB interface
5, 7, 9, 10
Table B-3: Possible default direct memory
access (DMA) channel assignment.
Usage
Default DMA
Channel
First DMA channel
0, 1, 3
Second DMA channel
5, 6, 7
